In common railroad track structure, steel rails are supported on wood crossties. The rails rest on tie plates and are attached to the crossties using a variety of fasteners. The track structure also includes rail anchors, which are applied to the base of the rail. Rail anchors are applied either by hand with a sledge or driven on using a rail anchor application machine. When applied correctly, the rail anchor is secured to the rail base with one side positioned next to the side of the crosstie. The function of a rail anchor is to efficiently dissipate rail force into the track structure. This is done by having the rail anchor remaining stationary on the rail base, transferring rail forces to the side of cross ties subsequently into the ballast and providing longitudinal restraint for the rail, e.g., to prevent rail movement from, for example, train dynamics, track topography, and rail steel thermal forces, expansion during high temperatures and contraction during cold temperatures. Expanding rail can produce sun kinks or a wavy pattern in the rail, making the rail unsafe for train traffic. Conversely, contracting rail can produce pull-aparts or breaks in the rail, which also lead to an unsafe rail condition. In most applications, rail anchors are “boxed,” meaning that four rail anchors are used per crosstie, with two rail anchors used per rail, each positioned on an opposite side of the crosstie. In tangent track, rail anchor patterns normally dictate that crossties be box-anchored at every other crosstie. It is also common for high-tonnage track to be box-anchored at every crosstie. Railroads also commonly box-anchor crossties at locations such as curves, rail crossings, when entering or leaving switches, and when entering or leaving bridges or tunnels. In general, when restricting rail movement is critical to maintaining the track structure, additional rail anchors are applied.
Wood crossties deteriorate over time; it is thus important to maintain maximum contact bearing area between the rail anchor and the crosstie that the rail anchor is contacting. Normal deterioration of a crosstie will occur initially at its edges and along the top of the crosstie, thereby leading to a potential loss of contact between the crosstie and the rail anchor. Any loss in contact area reduces the ability of the rail anchor to provide longitudinal restraint. In addition, the rail anchor most commonly used today can become embedded into the crosstie due to inferior bearing surface. Current rail anchor design used most commonly in the rail industry typically provides a rail anchor that has a contact-bearing surface area of about 2.9 square inches and weighs about 1.8 to 2.1 lbs., depending on the design.